Just bought a 98 ZJ 5.2 that has new 235 75 15's on the rear...wait for it...
and 215's on the front. 4H or 4L transfer case. Oh...and the front end "pops" as it rolls forward. I'm hoping its just axle hop from the different sized tires but worst case what am I looking at to fix if its not?

I'd pull the front driveshaft before you drive it anywhere else. The Vicious Coupler in the transfer case is probably burned up from different tire sizes($300 part). There's probably a front end rebuild in the future....

yup the vc is toast. also open up the front diff and check the gears and fluid. and remove the front drive shaft til you get it fixed. if the popping continues with the driveshaft out then check the axle shaft u joints or cv joints.

no kidding, some people I swear. The info is out there, and what tire shop said yea i'll throw on different size tires in the rear!

But yea vc is toast so doesn't matter, pull the front ds and make sure it drives ok besides that. Crack open the diff and see what it looks like. Hopefully when you get some correct tires it'll be ok up there, but things could be destroyed pretty easily. Good luck.

if it drove fine on the road then the transfer case is probably alredy shot. if the VC was shot it would be locked in 4wd and he'd have a hell of a time moving the jeep let alone driving it.
bet the chains gone. last ZJ i gutted had that problem.

took a long lunch and did some playing - dropped the forward drive shaft and the problem still exists. Hooked it back up, jacked up the left side and everything was good and tight. Jacked up the right side and it sounds nice and "crunchy" plus it will free-wheel when spun...and crunches while doing so. I'm guessing something ain't kosher inside the great pumpkin....